This invention generally relates to cardiovascular procedures such as angioplasty, angiography and valvuloplasty, and more particularly to an extendable guidewire for use in such procedures.
Guidewires are currently used to facilitate the placement of catheters in the arterial system of a patient for cardiovascular procedures such as angioplasty, angiography and valvuloplasty. The guidewire is typically on the order of 20-50 cm longer than the catheter to permit the guidewire and the catheter to be advanced relative to each other as they are steered into position within the patient's body. Suitable guidewires are described in U.S. Pat. No. 4,538,622 (Samson et al.) and U.S. Pat. No. 4,569,347 (Frisbie) which are hereby incorporated herein in their entirety.
In the usual procedure to change catheters, the guidewire is removed from the patient, and an exchange wire is inserted in its place. The in-place catheter is removed from the patient and a new catheter is inserted into the patient. The exchange wire is then removed and the guidewire is reinserted. The exchange wire is substantially longer than the guidewire, and it generally extends outside the patient's body for a distance greater than the length of the catheter. With a dilatation catheter having a length on the order of 120-140 cm, for example, a guidewire might have a length on the order of 175 cm, and an exchange wire might have a length on the order of 300 cm. The use of an exchange wire has the obvious disadvantage that it complicates the angioplasty procedure.
Heretofore, there have been some attempts to eliminate the need for a separate exchange wire by attaching an extension wire to a guidewire to extend the length thereof. The two wires are joined together by a crimped connector which requires a special tool. Once the wires have been crimped, the connection therebetween is permanent, and the extension wire cannot be removed except by severing it from the guidewire.
What has been needed and heretofore unavailable is an extension which can be readily connected and disconnected to the guidewire when it is in position within the patient. The present invention satisfies this need.